The invention relates to a two-stroke engine and a method for operating such a two-stroke engine, wherein the two-stroke engine comprises a fuel supply device in which a section of an intake passage is formed, wherein the intake passage upstream of the fuel supply device is connected to a clean air chamber of an air filter and wherein the intake passage downstream of the fuel supply device is divided by a partition into a supply passage for supplying substantially fuel-free air and a mixture passage for supplying a fuel/air mixture. In the section of the intake passage a throttle valve is pivotably supported and is aligned in at least one operating state with the partition.
U.S. Pat. No. 6,962,132 B1 discloses a two-stroke engine whose intake passage is divided into a mixture passage and an air passage. In order to prevent that fuel from the mixture passage is sucked into the air passage, the clean air chamber of the air filter is completely divided into two chambers.
It has been found that fuel from the mixture passage can pass into the air passage as a result of leaks in the area of the throttle valve. This is undesirable because this causes the exhaust gas values of the two-stroke engine to deteriorate.